Hypno Toad

This week's Wedge Issue: Wind Chill Factor is Pointless

Wind chill factor is great for The Weather Channel to hype cold temps and create drama, but it has very little effect when your riding a bike ... unless you're a nudist.

Here's the challenge for those that want to argue for wind chill: With the air temp is 35F/1.5C and the wind is 20 mph/32kph making the wind chill 24F/-5C, you put a glass of tap water on the patio table ... will the water in that glass freeze?

SPOILER ALERT! No, the water will not freeze until the air temp is below 32F/0C.

For rides when it's cold and windy, simply include a wind blocking layer and dress the same as you would for the air temp. Wind chill is about the lose of heat from exposed skin, and I don't know anybody going out with exposed skin when temps are cold enough to consider wind chill.

For reference, yesterday I rode for 90+ minutes with air temp at 0F/ and 6 mph winds, making the wind chill factor -12F/-25C. I dressed for the conditions, and a wind block layer is part of my winter kit any time the temps are below 45F/8C, regardless of the wind speeds (or wind chill factor) because riding a bike is creating a constant 10-20 mph (16-32 kpm) wind.

rumrunn6

I agree!

nice new winter photo, but why are you smiling ...? (JK totally rhetorical)

Hypno Toad

My face is frozen like that ...

burnthesheep

It is something I'd pay attention to when I do my lunch runs at work though. Eastern NC can be windy. A run at 35 deg and not much wind is shorts and a long sleeve t-shirt, no hat. A run at 35 deg and solid wind changes things. Hat, gloves, run tights, then depends on run pace the amount of layer/blocking happens on the upper body.

But on the bike, yes. Obviously given the constant drone of wind it's different. Especially different though when I ride slow hilly gravel in winter or take the TT bike out for a roll. That's a delta of nearly 10mph in average pace between the two. So I dress differently there also. Even 50 deg F on the TT bike can feel quite chilly if not well prepared.

mcours2006

I agree that windchill on a bike is less relevant. If I you're riding with a tail wind then it negates the windchill factor. However, the wind still works to take heat away from your body even if you are wearing a wind-blocking outer layer. So riding into a headwind you're getting a double dose of windchill. But wind is more of a factor in how hard your riding is going to be.

rumrunn6

spent 4 hours in a dentist chair yesterday. when I finally got up, my face was a bit frozen in place as well

MNBikeCommuter

The wind does make a difference even if you're dressed appropriately, but not as much of an impact as if on bare skin. If you light up a thermal camera while fully dressed, the wind will suck heat away faster than on a calm day. Plus, if your clothing isn't taped together/nice and tight where stuff meets, like my wardrobe, there'll be a little more breeze on the inside. That does help keep the inner stuff a little drier though, so it's not all bad.

But I may not be qualified to speak. I only made it 80+ minutes yesterday in the same conditions. I had a fender mount give way and after 100 feet of listening to the studs whir on the fender, I managed to temporarily jam the fender into an acceptable position that I wasn't sure was going to hold for the rest of the ride. It did, and new holes and zip ties have been added to that old fender for today's ride. It's a balmy 10F but that wind is gusting past 25mph. I'd take yesterday's 2F and 5mph wind over that...

Hypno Toad

It's a warm wind outta the south

Thulsadoom

One problem with wind chill in freezing conditions is you can't stop. If you do, the wind will suck the heat out of you in seconds.

_ForceD_

Yes. This is particularly bad if you have to stop for a maintenance problem…such as a flat…in a remote, dead cell zone area. Impossible to make the change with gloves on. Removing your gloves causes your hands/fingers to get so cold, quickly, that you can’t manipulate things to make the repair. Of course being in the cell dead zone…unable to call for a pickup…is another problem. All this has happened to me. Moral of the story: Stay in civilized areas during real cold rides.

Dan

SalsaShark

Trust me, wind makes a difference. Say I am comfortable at 15°f wearing similar head attire as your photo, ie: glasses, skull cap, helmet, fleece gaiter. I am fine with this attire if the wind is not blowing hard. Take the same exact riding conditions, and factor in a steady 20-25 mph wind and now life is miserable from the neck up. In these windy conditions, I now need a full balaclava head covering and goggles to keep my eyelashes from freezing shut, where as at the same temp and calm conditions, I was perfectly happy with exposed skin.
Drop the temp further, say -10°f. I can usually make my daily commute in these temps using my standard layering of mittens. Throw in a 20 mph headwind at these temps, and now we have to add chemical warmers to keep my fingers and thumbs from losing too much heat before my commute is finished. I would not necessarily want these adjustments without the wind, however, as it would be too easy to start sweating when my hands get too warm, and sweaty mittens can be a recipe for severe discomfort.
I will agree that for some, a windbreaker can solve issues on the torso and legs in windy conditions (although in my experience, this area never gets all that cold anyway, even in windy conditions - with the exception of the crotch), but the extremities will still need to be addressed accordingly to compensate for wind at lower temps.

sweeks

Wind chill is always good for bragging rights!

Hypno Toad

OME with the correct clothing, that's not an issue.

Hypno Toad

We need to dress for our unique body needs.

That said, wind is a very low priority when dressing for my daily winter rides. After air temp, it's sky conditions that are the next priority, sun versus cloudy or night. Snow plays a role too, but that's more an issue of how "fast" I can get where I'm going ... Unless temps are near freezing and I could end up getting wet. The wind, like snow, slows me down and taking longer to get where I'm going, but no real change in my clothing.

45NRTH Naughtvind shell pant are great alone at warmer temps and layered over wool bibs for colder temps. On the top I love my Podiumwear Arrowhead jacket and for the the wind and colder temps, I layer their wind vest under the jacket

To the point of a mechanical, working with bare hands ... that's exposed skin, and that's when wind chill is a factor. My winter tools include chemical hand warmers and light gloves. Trust me, 10+ years of winter riding, I've had my mechanical issues and know how to manage them.

sloppy12

20+mph headwinds suck when its sunny and 70 out.

MinnMan

Well, the other thing is how some people use wind chill (or "feels like") temperature to measure the conditions of their ride, when it's just not comparable.

Sorry, "it felt like -18 °F with the wind chill" is not the same as riding in air temperature of -18 °F.

And on a moving bike, the first statement is meaningless.

So there are two issues really - does wind or moving air speed affect heat loss, particularly from exposed skin? Yes. For a moving cyclist, is that effective temperature that you look up on your weather app meaningful? No.

Hypno Toad

From a detailed history of why wind chill is useless:

Wind Chill BlowsIt’s time to get rid of a meaningless number.

https://slate-com.cdn.ampproject.org...e-useless.html

rm -rf

I stepped outside this morning at 10F, 1-2 mph winds. "Feels like 10F". It didn't feel extremely cold.
It's rare to have the winds this calm when it's cold, so just about any cold day includes a bunch of wind chill. That's what most people remember when they are trying to compare temperatures on different days.

I don't ride much below 40F. But even at 40, I dress differently if the winds are 2-4 mph vs 12-15 mph. The brief stops are much colder, climbs are colder, and it probably affects flat road riding, too.

Sunny
It's mostly cloudy here in the winter. My rule of thumb is "8 degrees warmer" on a bright sunny day. That usually works very well for picking layers to wear.

Thulsadoom

I'm just wondering, are you saying that if it's 32F outside and the wind is blowing 15mph, you will stay just as warm on a bike as if it's 32F and there's no wind?

GhostRider62

Heat loss depends on many factors. Outside temperature, Cloud cover, relative humidity, manner of dress, metabolic efficiency of the rider, power output of the rider, cold adaptation of the rider, and yes.....apparent wind speed.

Hypno Toad

To be perfectly clear, this is BIKE Forums and this thread is about biking and wind chill.

From the linked article:

Directly addressing your question: Yes! If it's 35F, I'm wearing a wind blocking layer because on my bike, I'm generating a 10-20 mph wind by my motion. Regardless of winds at 15mph or still winds, a wind block layer doesn't change and I will stay just as warm with or with out winds blowing.

I'll add, once temps are around 20F, my wind blocking layers do not change ... even at temps down to -30F. One wind blocking layer is all you need, OTOH the layers of wool will increase as the mercury falls.

djb

I've been riding a bunch of days this month where in the morning its been -25c and a bit of wind, so feels like -35c+ and using my downhill skiing goggles and even my ski helmet makes a real difference. Ski goggle makes a real difference for not having my eyes water all over the place and keeps some of my old face from freezing too.
And have thrown another wind breaker layer on my legs (old rain pants) and my legs are ok.

I dunno, I find wind chill to make a real difference, but I'm a skinny old guy, so I just add some layers and specifically wind blocking stuff that makes all the difference.

Thulsadoom

Tightly woven wind block layers bring up the issue of moisture transfer.

djb

As a lifelong cross- country skier, same issue and the unzipping / zipping up routine, usually with climbing and descending..

Hypno Toad

I've had winds and rain proof gear that left me basting in my sweat, I've let all of that gear go as I've found items that are much better at managing moisture while blocking the wind/rain.

It's not cheap, but quality materials are good at blocking the wind and venting humidity. Well designed bike specific wind blocking layers have venting panels on the back side of the article of clothing where there's no wind. Additionally, well designed wind block layers include adjustable venting to dump heat when the body warms up. I'm a big fan of Podiumwear, 45NRTH, and Pearl Izumi AmFIB winter gear.

I'll repeat what I've said in earlier posts: while riding a bike, you're creating a 10-20mph wind; therefore, when air temps are cold enough to consider wind chill, wear a wind blocking layer regardless of the wind speed. One quality wind blocking layer is all you need, and adjust the layers of wool for the air temp.